It is known to provide the top sheets of diapers with transverse barriers for the purpose of preventing faeces from spreading to the front part of the diaper. EP-A-0,355,740 teaches such transverse barriers, which are created either by fastening strings of plastic foam to the top sheet or by creating transverse folds or pleats with the aid of elastic devices which extend in the longitudinal direction of the diaper in the crotch region thereof and therewith gather the top sheet together in this region. WO 94/14395 also teaches a corresponding type of transverse barrier in the outer sheet material.
The transverse barriers are intended to prevent faeces discharged to the rear part of the diaper spreading forwards in the diaper and dirtying the wearer's skin and genitals. The barriers also prevent urine and faeces mixing together on the diaper surface, since it is a known fact that the skin is much more sensitive to a mixture of urine and faeces than to each of the two components per se. Faeces contain certain enzymes which are believed to constitute an important factor in irritation of the skin. Urine is also liable to produce ammonia in the presence of faeces, therewith increasing the Ph, which in turn increases the enzymatic activity of said enzymes.
However, such transverse barriers are unable to prevent urine from spreading to the rear parts of the diaper via the underlying absorbent body and there being mixed with faeces, resulting in the aforesaid degradation products which are liable to cause skin irritation problems.